NPIF: Photobioreactors for sustainable production of plant-driven biocompounds

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Biological Sciences


From papers, fabrics to wood products, plants generate most of the natural materials used in our environment [1]. Plants also supply medicines, dyes, spices, and other specialized chemicals. While biotechnology has blossomed into industrial scale cell culturing for microbial and mammalian systems, plant cells are scarcely used; interestingly, plant-driven products are generated in other organisms via transgenic introduction of plant pathways [2]. Why are plant cells overlooked in industrial biotechnology? According to representatives of major companies in the field, the problem is simply that the tools and protocols are underdeveloped for industrial plant cell biotechnology, such as the suitable bioreactor platforms and the availability of high efficiency cell factories.

Plant cells tend toward frail in typical bioreactors developed for microbes and mammalian cells; they are sensitive to the shear stress caused by mechanical mixing of the medium. Furthermore, even though plant cells are autotrophic, they need supply of a high amount of sugar inside traditional bioreactors devoid of light. Ironically, the sugar content increases the risk of microbial contamination and infection. Therefore, bioreactors that allow photosynthesis (i.e. photobioreactors) should be developed for plant cell culturing. The biotechnology company Xanthella has established versatile photobioreactors for culturing diverse algae species [3]. Their systems supply air via tubes and thus do not involve mechanical mixing of the medium, and they come in a wide range of scales. Underdeveloped tools also extend to the selection of plant cell factories; the Nakayama Group at the University of Edinburgh is developing a synthetic biology toolbox to create plant cell factories with enhanced capabilities to produce specific types of biocompounds.

This PhD project aims to establish a robust, low-cost, and scalable platform for plant cell culturing and thus plant cell-based industrial biotechnology. Combining the novel Arabidopsis cell factory lines with Xanthella's photobioreactors, we will develop two enabling innovations for plant cell-based industrial biotechnology: the suitable bioreactors and sophisticated toolbox for precision control of the cell activities.


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Description - In order to proceed with my initial goal (differentiating plant cell cultures into specialised cell types to make use of their innate production capabilities or cell shapes), I had to work on developing new tools and protocols for use in synthetic plant biology, since there were not enough for me to work with. This step is largely complete. We have newly developed and characterised a whole suite of promoters and terminators ('start' and 'stop' signals for genes), as well as having developed new plasmids and protocols than can be used in plant systems.
- As part of our characterisation studies, we found that both promoters and terminators can have a marked effect on gene expression levels. The findings regarding terminators having strong effects are very interesting, since they have been widely disregarded as having much of an impact on gene expression until now. We are in the process of writing these findings up for publication.
- We have developed protocols for the rapid creation and transformation of protoplasts (plant cells with no cell wall), which can be a laborious task when working with many samples. Thanks to our protocol (in press), researchers will hopefully be able to do it at a large scale in 96-well plates in the future.

I am currently working on the initial goal of the project (differentiation of plant cells in culture) using the tools and methods we have developed.
Exploitation Route SO FAR:
- Developed protocols (e.g. high-throughput protoplast transformation, in press) can be used by other research groups
- Novel and fully characterised standard parts for use in plant synthetic biology can be used by other research groups
- Findings on terminator strength on gene expression levels (in press) can be taken into account by other research groups and aid them in their studies
- Findings on PCC growth in Xanthella bioreactors is aiding them in their design adaptations for different species

- (if successful) growth of paper pulp at a small lab scale could be a potential starting stone to develop a new and environmentally friendly alternative to current industrial paper production (tree felling and de-lignification of wood are environmentally damaging).
Sectors Environment,Manufacturing, including Industrial Biotechology,Other

Description Edinburgh Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact I was a demonstrator for the Edinburgh University School of Biological Sciences stalls at the science festival the last two years, and will do so again this year.

Whilst the stalls and activities are aimed at children and cover a wide range of biological subjects (not related to my own project), demonstrators still always had the opportunity to discuss their own research. These discussions happened with adults, peers, parents, teachers but also children asking about what I did, and I had to tailor my explanations accordingly. These discussions were always very well received, with the public showing great interest in research conducted at the university.
Year(s) Of Engagement Activity 2018,2019,2020